KR20090016221A

KR20090016221A - The structure of pusher type heating furnace

Info

Publication number: KR20090016221A
Application number: KR1020070080705A
Authority: KR
Inventors: 김영복
Original assignee: 주식회사 포스코
Priority date: 2007-08-10
Filing date: 2007-08-10
Publication date: 2009-02-13

Abstract

A pusher type furnace is provided to maintain a predetermined temperature for a furnace by circulating heat inside the furnace, thereby preventing degradation of a heating-up rate for a slab. A pusher type furnace comprises the units. A preheating board preheats a slab(110) for a thick plate and a heating board(100) heats the slab. A soaking zone soaks the slab. A top expansion unit(H2) and a bottom expansion unit(H3) expand the heating board and reduce the preheating board by pushing a border part between the preheating board and the heating board toward the preheating board. The fourth, fifth, sixth, seventh heating torches(200,210,220,230) are installed on the heating board.

Description

Pusher type furnace structure {TH STRUCTURE OF PUSHER TYPE HEATING FURNACE}

The present invention relates to a pusher-type heating furnace structure, and more particularly, to pusher-type heating furnace which minimizes the temperature deviation inside the furnace so as to secure a uniform crack degree without cracking the slab for thick plates that pass through the heating furnace before rolling. It's about structure.

In general, in the hot rolling and rolling process of the steel mill, a heating furnace is provided to heat the slabs produced through the reproducing process.

Usually, the control of the metallurgical conditions, dimensions and appearance of the slab's corresponding standard is carried out in the actual rolling line, but for more accurate control the heating of the slab uniformly to the desired temperature, especially in the width direction, as well It is required to be uniformly heated in the longitudinal direction.

This operation is very important in furnaces because it reduces metallurgical variation in metallurgy and thickness variation in terms of dimensional control.

For example, as illustrated in FIGS. 1 and 2, in the heating furnace 1, skid pipes 3 are arranged on the bottom thereof, and slabs 2, which are raw materials, are continuously seated on the upper portion thereof, and the charging pusher 4 is disposed. According to the charging operation of the slab (2) is made of a form that is gradually moved to the discharge side after extraction.

Further, the heating furnace 1 is divided into a preheating zone, a heating zone, and a cracking zone from the charging side to the extraction side in the longitudinal direction thereof, and according to the conditions such as the initial temperature of the charging slab 2 and the final temperature required for extraction. The heating rate and residence time in the preheating zone, heating zone, and cracking zone are controlled differently.

To this end, the first heating burner 5 is installed at the upper part of the heating table 1 of the heating furnace 1, and the second and third heating burners 6 and 7 are installed at the lower part of the heating table 1 to face each other, thereby ensuring cracking. The crack burner 8 is installed in the upper part of the crack stage.

By the way, in the heating furnace 1 of such a structure, as shown in FIG. 2, the upper part of a heating stand is empty in a heating stand, and the upper part of a cracking stand is empty in a cracking zone (there is no heat source), and the slab 2 is heated rapidly and a temperature is raised for a short time. There was a disadvantage in that the speed could not be uniform, and in the slab (2) side where there is no heat source, the temperature kept dropping, resulting in a difference in temperature rise rate, and in addition, temperature rising unevenness caused the deterioration of the final product. Will result.

For example, as shown in FIG. 3, the slab 2 was preheated and heated as a result of checking the change over time while measuring the temperature profile at three points of 250 mm, 220 mm, and 203 mm in the thickness direction. It was found that the temperature increase rate was dropping at all three points for 50 to 70 minutes passing through.

On the other hand, when passing between the heating zone and the cracking zone, the temperature deviation was extreme, and it was also confirmed that the cracking degree could not be sufficiently secured.

This phenomenon was found to be due to the installation of a large number of burners as heat sources.

The present invention has been made in view of the above-mentioned problems in the prior art, and has been created to solve the above problem, and deforms the internal structure of the furnace to reduce the temperature deviation due to the heat circulation in the furnace, uniform in a short time at a rapid temperature rise The main problem is to provide a pusher type heating furnace structure that improves the quality of the final product by distributing the burner, which is a unilaterally installed heat source to achieve a temperature rising rate, to prevent the slab temperature rising rate from dropping.

The present invention is a pusher type heating furnace structure consisting of a preheating stage for preheating a slab for thick plates, a heating stage for heating, and a cracking zone for cracking as means for achieving the above-described problems; Upper and lower portions of the upper and lower portions of the portion where the preheating zone and the heating zone are in contact with the preheating zone to reduce the preheating zone and extend the heating zone; A fourth, fifth, sixth and seventh heating burners installed at four positions at the top and the bottom of the heating table; It provides a pusher type heating furnace structure, characterized in that composed of the first and second crack burners installed at both the upper and lower portions of the starting point of the crack.

In this case, the first and second trimming walls protruding downward in the middle ceiling surface of the heating table may be further formed.

In addition, the first and second trimming walls are sequentially formed at intervals from the preheating zone toward the cracking zone, and the second and second trimming walls are formed longer than the first trimming walls.

According to the present invention, the heat circulation inside the furnace according to the change of the internal structure of the furnace is smooth to prevent the slab temperature rise rate decreases, uniform heating operation can be performed, and by minimizing the slab temperature drop at the exit side of the furnace The quality of the final product can be improved and thus the productivity will be improved.

Hereinafter, on the basis of the accompanying drawings will be described in detail a preferred embodiment according to the present invention.

Figure 4 is a schematic diagram showing the internal structure of the heating furnace according to the present invention, Figure 5 is a front view as seen from the main portion C, D of Figure 4, Figure 6 is a graph showing a heating pattern of the heating furnace according to the present invention.

As shown in Figure 4 and 5, the heating furnace 100 according to the present invention is pre-heated as before, so that the slab 110 can be preheated, heated, cracked when moved along the skid pipe 120, It is divided into heating zone and cracking zone.

At this time, in the present invention, the upper and lower portions of the heating table 100 are further pushed toward the preheating zone so that the space of the heating table becomes larger than the width of the conventional heating table ('H1' in FIG. 1), and thus the upper extension portion H2 and the lower extension portion H3. It is configured to have).

Accordingly, the heating furnace 100 according to the present invention has a structure in which the heating table is extended and the preheating table is reduced, so that the furnace body has a substantially flat structure in the longitudinal direction.

Four, five, six, seven heating burners (200, 210, 220, 230) are respectively provided on the upper and lower four places of the heating stand, that is, the upper and lower portions of the heating point start point and the upper and lower portions of the heating point end point. Is formed.

In addition, the first and second trimming walls 300 and 310 protrude downward in the middle portion of the heating table.

In particular, the first and second trimming walls 300 and 310 are preferably sequentially formed at intervals from the preheating zone toward the cracking zone.

At this time, the second trimming wall 310 is formed to be longer than the first trimming wall 300 so that the flow of heat entering from the preheating zone is turned downward without flowing to the ceiling surface of the heating table and then flows again. Prolonging residence time and facilitating convection provide the desired temperature profile for heating zone elevated temperatures.

In addition, the first and second crack burners 400 and 410 are installed in the upper and lower portions of the cracks, respectively, so that the heat through the heat source can be supplied at the same time.

The efficiency of the heating table structure according to the present invention having such a configuration will be described with reference to the graphs attached to FIGS. 4, 5 and 6 described above.

First, as compared with the graphs of FIGS. 3 and 6, in the related art, although the temperature drop of the slab, that is, the lowering of the temperature increase rate, has been shown between the preheating zone and the heating zone, the present invention is raising uniformly without decreasing the temperature rising rate. You can see that.

As mentioned above, this is because the amount of radiant heat is increased by the expansion of the heating furnace by the upper extension part H2 and the installation of the sixth heating burner 220 that has not existed previously.

That is, the elevated temperature of the slab 110 started from the preheating zone is steadily rising rapidly with a certain slope until passing through the preheating zone and the heating zone.

In addition, according to the present invention, because the slab 110 is shortened to the inside of the furnace 100 by the time it takes for the slab 110 to heat up to the target temperature passing through the heating table, the productivity of the slab 110 is shortened. do.

In addition, the heat of the heated heat does not move immediately to the vicinity of the cracking zone immediately after the ceiling surface of the heating table, heat waves are generated by the first and second trimming walls 300 and 310 protruding about the middle of the ceiling of the heating table. The longer the residence time of the heat, the shorter the temperature rise time can be performed more uniform temperature operation.

In addition, since the heating operation takes place in both the upper and lower portions of the furnace, the amount of heat is sufficient, thereby reducing the heating time.

In this way, the slab 110 passing through the heating table is supplied with sufficient heat from the first and second crack burners (400,410) installed in the upper and lower parts of the crack even after arriving in the crack, it is possible to heat until extraction, so sudden temperature during extraction The fall is prevented, so that subsequent rolling operations can be performed more smoothly.

1 is a schematic view showing the internal structure of a conventional heating furnace,

2 is a front view seen from the main parts A and B of FIG.

3 is a graph showing a heating pattern of a conventional heating furnace,

Figure 4 is a schematic diagram showing the internal structure of the heating furnace according to the present invention,

5 is a front view as seen from the main portion C, D of FIG.

Figure 6 is a graph showing a heating pattern of the heating furnace according to the present invention.

♧ description of the symbols for the main parts of the drawing ♧

100 .... 110 by heating ... slab

200..Fourth heating burner 210 .... Fourth heating burner

220 .. 6th heating burner 230 .... 7th heating burner

300 .... First cliff 310 .... Second cliff

400 .... 1st crack burner 410 ... 2nd crack burner

Claims

In the pusher type heating furnace structure which consists of a preheating stage which pre-heats a slab for thick plates, a heating stage to heat, and a cracking zone to crack;

Upper and lower portions of the upper and lower portions of the portion where the preheating zone and the heating zone are in contact with the preheating zone to reduce the preheating zone and extend the heating zone;

A fourth, fifth, sixth and seventh heating burners installed at four positions at the top and the bottom of the heating table;

Pusher heating furnace structure, characterized in that consisting of the first and second crack burners installed in both the upper and lower parts of the starting point of the crack.

The method according to claim 1;

A pusher type heating furnace structure, characterized in that the first and second trimming walls protruding downwards are formed on the length of the middle ceiling surface.

The method according to claim 2;

The first and second trimming walls are sequentially formed at intervals from the preheating zone toward the cracking zone, and the pusher-type heating furnace structure is characterized in that the rear second trimming wall is formed longer than the first trimming wall.